Question of the week 11-Mar-2020

Q) The biggest possible three digit number "abc" such that (a x b x c) + (a x b) + (b x c) + (a x c) + a + b + c = 29 is
a)  421      b) 307         c) 540        d) None of these

Previous question here. Next week question here. It is solvable in less than a minute provided you know the trick that i will be discussing in the book. Your answer only with a logical explanation is welcomed in the comments section.